Conventional primary cell batteries produce electric current through a chemical reaction. In particular, an oxidation-reduction reaction is carried out in such a way that its driving force produces an electric potential. The oxidation-reduction reaction is achieved by providing an oxidizing agent and a reducing agent which is separated from the oxidizing agent. The oxidizing agent removes electrons from one electrode and the reducing agent gives electrons to another electrode, the flow of current through the battery being carried by ions. A common dry cell battery is one type of primary cell battery.
The common dry cell battery comprises a zinc cylinder which acts as one electrode and contains a suitable electrolyte, such as a paste of ammonium chloride (NH.sub.4 Cl), zinc chloride (ZnCl.sub.2), water (H.sub.2 O) and diatomaceous earth or some other filler. A carbon rod and a surrounding paste, which includes a mixture of maganese dioxide (MnO.sub.2) and carbon particles, functions as the other electrode.
Deferred action dry cell batteries have been known for many years. One object of a deferred action dry cell battery is to prevent the battery from deteriorating and becoming inoperable prior to use as a result of a secondary chemical reaction between the electrolyte and the electrodes of the battery.
In one type of deferred action battery, the electrolyte is stored in a first compartment while the electrodes are housed in a second compartment. When the battery is to be activated, the electrolyte is transferred from the first compartment to the second compartment. The provision of two separate compartments is, however, undesirable because it increases the overall size of the battery. Increasing the size of the battery is disadvantageous because it can result in increased construction and shipping costs. If the size of the battery is increased, there is also a possibility that the battery will not be compatible with electrical devices designed to accept a standard-sized battery.
Another type of deferred action dry cell battery is manufactured with the electrolyte and the electrodes in a single compartment, a chemically inactive liner being interposed between the electrolyte and the electrodes to prevent premature activation of the battery. The battery is activated by removing the liner to expose the electrodes to the electrolyte. Huntley U.S. Pat. No. 1,407,035 and Zaromb U.S. Pat. No. 3,332,804 disclose deferred action batteries employing such a liner.
The deferred action battery disclosed in the Huntley patent utilizes a liner which in its inactive position is coiled inside of a zinc can, the zinc can acting as an electrode of the battery. The liner overlaps itself within the zinc can so as to shield the zinc can from an electrolyte solution contained therein. In order to activate the battery, the zinc can is rotated to draw the liner out of the zinc can through an aperture or slot therein. The rotation of the zinc can coils the liner around the outside of the zinc can, thus physically removing at least a portion of the liner which shields the zinc can from the electrolyte when the battery is inactive. By making the liner sufficiently stiff, it may be reinserted between the zinc can and the electrolyte by rotating the zinc can in an opposite direction. The movement of the liner through the aperture or slot, which extends along the entire length of the battery, creates sealing problems which could result in the loss or drying out of the electrolyte.
The Zaromb patent discloses a deferred action battery comprising a plurality of radial cell compartments, each of which is enclosed by a sealing gasket and by a pair of thin coils covering the anode side and the cathode side of bipolar electrodes. The compartments are filled with a suitable electrolyte which is normally maintained out of contact with the electrodes by the foils. To activate the battery, a central shaft is rotated with respect to the radial cell compartments until all of the foils are withdrawn from the respective compartments to expose the electrodes to the electrolyte. The physical withdrawal of the foils from the radial compartments causes sealing problems. In addition, the foils do not appear to be designed for reinsertion between the electrodes and the electrolyte so as to deactivate an activated battery.